Description
HA12155NT/HA12157NT is silicon monolithic bipolar IC providing Dolby noise reduction system*, electrical volume system, REC equalizer system and level meter system in one chip.

Features
• Inductor less REC equalizer is adjustable of its characteristics by external resistor
• Rec level is adjustable automatically with electrical volume which is built-in
• 3 type of input selection is available (one is by way of electrical volume)
• Separate input selection SW and REC/PB SW
• Dolby noise reduction with dubbing cassette decks
   (Unprocessed signal output available from recording out terminals during PB mode)
• Log-compressed level meter output is range from 0 V to 5 V
   (Usable as music search switchable gain of 0 dB and 20 dB respectivily)
• Normal-speed/high-speed (Double), normal/metal/chrome fully electronic control switching built-in
• NR-ON/OFF, Dolby B/C, MPX ON/OFF fully electronic control switching built-in
   (Controllable from micro-controller directly)
• Reduction of number of pin by transfered serial data to electronic volume control switching and another
   control switching
   (Controllable from micro-controller directly)
• Low external parts count